Rolling Thunder revved up today for the non-profit organization's annual "Ride For Freedom" in Washington, D.C.

The 28th annual event brought hundreds of thousands of bikers and spectators together to honor America's veterans, especially those who are missing in action.

Doug McKelway reported on "America's News Headquarters" that at noon today, thousands of bikers took off from the overflowing north parking lot of the Pentagon, heading to the Lincoln Memorial, where the ride ends.

"It is an incredible sight, and if you don't like the sounds of Harley Davidsons, it's not a great day to be in Washington," McKelway remarked.

"The rally has broadened out considerably over the past several years, basically to pay tribute to veterans and those who have fought for the United States in whatever capacity," McKelway reported. "That's why these people are here today."

Watch the "America's News Headquarters" clip above and get more information on Rolling Thunder.